High-density packages are ordinarily used due to increased numbers of the electronic elements actually installed on printed wiring boards and reduced size of printed wiring boards.
The more the high-density packages are used, the more the routes of electric currents in the printed wiring boards complicated. Thus, problems such as impedance mismatching and crosstalk are apt to occur. More advanced circuitry designs are in prospect for these printed wiring boards.
Circuitry designs for the printed wiring boards having high-density packages may be accompanied by a vast amount of calculations. Therefore, various apparatuses may be used in supporting the circuitry design. Examples of the various apparatuses are an apparatus for calculating appropriate wiring structures, an apparatus for calculating areas of wiring patterns, and an apparatus for producing equivalent circuit models by considering minute vacancies in patterns (openings).
[Patent Document 1] Japanese Laid-open Patent Publication No. 2001-331539
[Patent Document 2] Japanese Laid-open Patent Publication No. 09-81602
[Patent Document 1] Japanese Laid-open Patent Publication No. 2008-15636